Can they be extended to children conceived after their father's death? A New Jersey case has gotten the attention of U.S. servicemen, some of whom use sperm banks before deploying.

Reporting from Washington — The Supreme Court justices struggled with applying an "old law to new technology" in a case that asks whether children whose father died before they were born or even conceived are entitled to survivors benefits under the Social Security law.

The justices heard the case of Karen Capato, a New Jersey mother who in September 2003 gave birth to twins through in vitro fertilization 18 months after her husband, Robert, had died of cancer in Florida.

The couple had married in 1999, but not long afterward, Robert was diagnosed with esophageal cancer. They had one child, and the husband deposited semen in a sperm bank as his condition worsened. After his death at age 44, his wife became pregnant with the twins.

Since 1939, the Social Security Act has offered benefits to the survivors of a deceased wage earner, including dependent children.

When Karen Capato applied for survivors benefits for the twins, a Social Security official said she had a "very sympathetic case," but turned down the request nonetheless. The Social Security Commission said that because the twins were not heirs of the father at the time of his death, they did not qualify as his survivors.

The issue has divided judges across the country. It has also gotten the attention of U.S. servicemen overseas, some of whom have used sperm banks before deploying for a war zone.

In the Supreme Court on Monday, a Justice Department lawyer defended the commission's view of the law. One provision says a surviving child is one who is "dependent on the deceased wage earner at the time of [his] death." Since the twins were not yet conceived, they could not have been dependents at the time of his death, he argued.

The Yale Law Clinic, representing Karen Capato, argued that the twins were the biological children of a married father, and therefore qualified for benefits as his survivors. They also noted that Robert Capato had told his attorney he wanted to provide for "unborn children" after his death, although that provision was not included in his will.

Through most of the argument, the justices voiced doubt that the law was intended to extend benefits so broadly to children who were not yet born or conceived.

Justice Antonin Scalia said its wording "disfavors children who were born after the father has died." He pointed to the discussion of survivors benefits. "What is at issue here is not whether children born through artificial insemination get benefits. It's whether children who are born after the father's death get benefits," he said.

Chief Justice John G. Roberts Jr. asked, "What if the children — the Capato twins — were born four years after the death" of the father?

Charles Rothfeld, the lawyer for Karen Capato, said the time lapse would not matter. Roberts questioned whether the definition of a survivor could be stretched far into the future.

Justice Stephen G. Breyer said he too was skeptical of "applying this old law to new technology."

Near the end of the arguments, the chief justice said the court usually deferred to a government agency when its interpretation of the law was reasonable. "You lose if the statute is ambiguous," he told Rothfeld. "Is there any reason based on the last half hour that we shouldn't conclude it's at least ambiguous?" he said to laughter.

"It's a mess," interjected Justice Elena Kagan.

It will likely be several months before the court rules in the case of Astrue vs. Capato. If the court rules that survivors benefits are limited to children who were conceived before the father's death, Congress could still revise the law.